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Post by protools1 on Feb 6, 2022 3:35:45 GMT
Thank again. I appologize if I am not quite grasping it. Are you suggesting that in a "good/proper" room the sound decays should be louder at lower frequencies, specially in time like after 100 or 150ms of measurements?
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Post by Hexspa on Feb 6, 2022 10:31:24 GMT
That's just kind of how it goes. The low end decay will be longer. I think the goal is to make it smooth i.e. no resonances interrupting the taper. You can check p.6 of this document: tech.ebu.ch/docs/tech/tech3276.pdf
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Post by protools1 on Feb 21, 2022 4:01:28 GMT
just realized i never thank you and this forum for being so helpful
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Post by Hexspa on Feb 21, 2022 11:29:16 GMT
All credit to Mr. Winer.
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Post by protools1 on Mar 3, 2022 21:55:19 GMT
yes thank you Mr Winer. I got another question and wonder if i start another thread. But here it goes. Flush mounted big speakers in the wall the wall on spec it says it goes down to 50Hz. Looking at ATC SCM 300 on their website it said Amplitude Linearity (±2dB): 50Hz-12kHz Cut-off Frequencies (-6dB): 25Hz-20kHz (free standing) 20Hz-20kHz (soffit mounted) So does it mean properly mounted it should be expected to reach 20Hz even. I'm asking because it seems like the ones i am dealing with have not been properly mounted. In fact can they be properly mounted and I can walk under the wall mount ? Doesn't the wall need a lot of mass?
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Post by Hexspa on Mar 4, 2022 12:21:00 GMT
I'm not knowledgeable about soffit-mounting but I'm sure someone here will straighten us out.
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Post by rock on Mar 9, 2022 19:55:20 GMT
Good questions. I'm just trying to keep the conversation going. As Hexspa says, someone else here will straighten us out. We can only hope! For now, this is what I got: I'm not sure this will answer the question but it might help explain the different cut-off frequencies quoted. Here's the link: www.prosoundtraining.com/site/wp-content/uploads/2012/03/VOL36_DEC08_Boundaries-1.pdfYou also ask "Doesn't the wall need a lot of mass? Well we know that if you have a very low mass wall like paper, most LF and Mid-range spectrum will go right through and reflect on HF. I'm sure your walls are not paper One layer of 5/8 drywall on 16" studs reflects most LF plus it resonates (absorbs) a little and transmits some through too. I don't know how much of each but as the mass goes up, the more LF is reflected and the less is transmitted and the lower it resonates. So I'd say yes, the wall needs mass...but how much? Sorry I don't know, but if you're also building for low transmission, you should use at least 2 sheets 5/8 dry wall on each side of the wall. But that's for sound isolation to other rooms. I imagine that kind of mass might also be enough to form a suitable reflective barrier to get down to 20Hz...but even one sheet like in regular construction will probably be sufficient within a reasonable margin...my best guess
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